Over the past few years, biofilms have become a major concern in many different industries such as food-processing, maritime transport, aquaculture, offshore drilling but also in the domestic and medical environment.
Biofilm formation is a process comprising three different steps. The first step consists in the attachment of mobile microorganisms, such as bacteria and microalgae, on a surface. In the second step, the microorganisms produce polysaccharides which consolidate the interface between the microorganisms and the surface. The final step leading to a biofilm involves colonization, growth and division of the microorganisms on the surface. A fully developed biofilm will contain an exopolymeric matrix and mushroom-shaped structures separated by interstitial spaces. Biofilms have a heterogeneous structure and are capable of mass internal transport.
In a marine environment, biofilms are subsequently colonized with macrofoulers, such as macroalgae and invertebrates. Marine biofouling is an invasive phenomenon causing significant problems on immerged marine structures used in the shipping, aquaculture and offshore petroleum industry, such as an increase in weight, fuel consumption and frictional drag.
Conventionally, metal-based paints have been used to control development, maturation, and growth of biofouling processes. Organotin-based paints have especially been used due to their biocide properties and their efficiency to prevent marine fouling. Unfortunately, organotin coatings were found to adversely affect the environment due to the collateral damage inflicted on the marine ecosystem and non-target species. Organotins are now banned from use by the International Maritime Organisation (IMO) and there is thus a need for non-toxic compounds that can effectively prevent biofilm formation.
After extensive research, Applicant has found that bis-triazole compounds of general formula (I) exhibit excellent anti-biofilm activities. Surprisingly, these compounds also exhibit excellent anticorrosion properties. Since corrosion is another problem frequently encountered in immerged marine structures, the compounds of the present invention can advantageously be used to simultaneously protect said structures from fouling and corrosion.